30,126 research outputs found

    Interim report on the ground-water resources of Seminole County, Florida

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    Salt-water encroachment is undoubtedly the problem of most concern to users of ground water in Florida. This is a problem in many coastal areas where water levels are lowered excessively by heavy pumping. It is a problem also in some inland areas where the water-bearing formations contain salty water at relatively shallow depths. Among the coastal areas where wells have become contaminated with salt water are Pinellas County and the Miami area of Dade County. Inland areas where wells are likely to become contaminated with salt water include Seminole County and the southwestern part of Volusia County. The purpose of the investigation is to make a detailed study of the geology and ground-water resources of the county with special emphasis on the problems associated with declining water levels and salt-water contamination. This report reviews briefly the progress of the investigation through February 1954. (PDF contains 43 pages.

    Radioisotope thermionic power supply for spacecraft

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    Power supply design for unmanned electric propulsion missions to outer planets utilizes a store of curium-244 in compact array of capsules as energy source. Supply subassemblies are: heat source, converter equipment which supplies power, and safety equipment. System is designed for a 72,000 hour mission

    Factors affecting breeding status of wading birds in the Everglades.

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    This goals of this research and monitoring effort are to document nesting effort and roughly categorize success of nesting by wading birds in the central Everglades of Florida, and to investigate the causes of nonbreeding in a high proportion of the adult wading birds in the ecosystem The latter goal has focused on breeding of White Ibises (Eudocimus albus) and has been approached through 1) understanding the nutritional, behavioral, and hormonal aspects of normal breeding in a captive colony ofScarlet Ibises (considered conspecific to White Ibises) in central Florida, and 2) comparing breeding and nonbreeding wild White Ibises in the Everglades, in their physiology, nutritional state, breeding phenology, contaminant load, and hormonal status. This report covers work on this project between January and November, 2000. (81 page docoument

    Postal survey of contacts between cattle farms on the Isle of Lewis

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    The British Cattle Movement Service (BCMS) database contains an unprecedented quantity of data on the movement of cattle within the UK. These data may be used to construct models of the contact structure of the UK cattle herd, for epidemiological purposes. There are two significant potential sources of inaccuracy within such models: movements that are not reported or are reported inaccurately to the BCMS, and contacts between farms that might transmit infection, but are not animal movements. This field study addressed these issues. Cattle farmers on the Isle of Lewis were recruited with the assistance of the local veterinary surgeon, and asked to record a range of potential risk behaviours for a one-month period. They were also asked questions about husbandry practices on their farm. Comparison of the BCMS contact data with that reported by Lewis' farmers highlighted use of common grazing land as a significant source of contact, and potential disease transmission, between cattle that currently goes unreported; around half of responding holdings on Lewis use common grazing land at some point during the year, and these movements are not reported to the BCMS

    Letter to the Editor: a response to Horne and Lucey (2017)

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    A Vaccine Against Group B Streptococcus: Recent Advances

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    Group B streptococcus (GBS) causes a high burden of neonatal and infant disease globally. Implementing a vaccine for pregnant women is a promising strategy to prevent neonatal and infant GBS disease and has been identified as a priority by the World Health Organisation (WHO). GBS serotype-specific polysaccharide – protein conjugate vaccines are at advanced stages of development, but a large number of participants would be required to undertake Phase III clinical efficacy trials. Efforts are therefore currently focused on establishing serocorrelates of protection in natural immunity studies as an alternative pathway for licensure of a GBS vaccine, followed by Phase IV studies to evaluate safety and effectiveness. Protein vaccines are in earlier stages of development but are highly promising as they might confer protection irrespective of serotype. Further epidemiological, immunological and health economic studies are required to enable the vaccine to reach its target population as soon as possible

    Sums and differences of four k-th powers

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    We prove an upper bound for the number of representations of a positive integer NN as the sum of four kk-th powers of integers of size at most BB, using a new version of the Determinant method developed by Heath-Brown, along with recent results by Salberger on the density of integral points on affine surfaces. More generally we consider representations by any integral diagonal form. The upper bound has the form ON(Bc/k)O_{N}(B^{c/\sqrt{k}}), whereas earlier versions of the Determinant method would produce an exponent for BB of order k1/3k^{-1/3} in this case. Furthermore, we prove that the number of representations of a positive integer NN as a sum of four kk-th powers of non-negative integers is at most Oϵ(N1/k+2/k3/2+ϵ)O_{\epsilon}(N^{1/k+2/k^{3/2}+\epsilon}) for k3k \geq 3, improving upon bounds by Wisdom.Comment: 18 pages. Mistake corrected in the statement of Theorem 1.2. To appear in Monatsh. Mat
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